In the clinical and pharmaceutical arts, brewing, food and chemical manufacturing industries, redox reactions are of great interest for the determination of various chemical and biological substances, called analytes herein. In many cases, these analytes are enzymes, substrates for enzymes, or microorganisms which contain enzymes which can participate in redox reactions. Generally, these reactions are evaluated photometrically by determining the formation or disappearance of a chromogen or fluorogen.
However, in many fluids which are being analyzed, such as biological fluids, there are substances which are strong reducing agents and can act as interferents by prematurely causing dye formation. Ascorbic acid is one such substance. Ascorbic acid, or Vitamin C, is a common interferent found in the body fluids of many people. According to U.S. Pat. No. 4,168,205 (issued Sept. 18, 1979 to Danninger et al), unwanted ascorbic acid can be removed by converting it to dehydroascorbic acid by the action of ascorbic acid oxidase. In many instances, this technique sufficiently removes the interference in the assay.
However, in some assays, dehydroascorbic acid can still be a significant interferent. For example, in assays where reducible compounds are used to provide a detectable species, the presence of even a small amount of a reductant such as dehydroascorbic acid can cause a significant error.
Therefore, it would be desirable to have a means for eliminating the interfering effect of dehydroascorbic acid in any assay utilizing a reducible compound.